Alarm devices



W. W. WEESE ALARM DEVICES April 13, 1965 3 Sheets$heet 1 Filed Feb. 17, 1964 INVENTOR. WILFRED W. WEESE FIG. 3

KW, $6 I l;

A TTOR NE Y5.

April 13, 1965 3 Sheets-Sheet 2 Filed Feb. 17, 1964 muJL; Y3.

FIG. 5

United States Patent 3,177,842 ALARM DEVICES Wilfred W. Weese, Middle Village, N.Y., assignor to Harry Swartz, New York, NY. Filed Feb. 17, 1964, Ser. No. 345,280 8 Claims. ((Zl. 116-106) This invention relates to condition responsive alarm devices useful for signalling a fire alarm or other emergencies and more particularly to mechanically operated self-contained alarm devices.

In the design and construction of an alarm device for signalling an emergency such as a fire, for example, it scarcely needs to be said that reliability in operation is an especially important characteristic. Independence of reliance upon external sources of operating energy is a valuable feature related to reliability of any alarm device, since an emergency condition might otherwise disrupt the power to the alarm device or system and prevent it from signalling the emergency. Anotherfeature especially important in an alarm device is the distinctiveness of its alarm signal. An alarm signal which lacks distinctiveness may easily be ignored for its failure to impress its urgent message on those in its vicinity.

It is a principal object of this invention to provide an especially reliable condition-responsive alarm device which is mechanically operated from a self-contained source of power to produce an insistent attention-getting alarm upon the occurrence of an emergency condition.

I A further object of this invention is to provide an improved mechanically driven alarm device which produces a sound signal having an insistent rising and falling characteristic for the purpose of signalling an alarm condition.

, A still further object of the invention is to provide a reusable and resettable thermally responsive alarm de vice which is reliable and attention provoking.

By way of a brief summary of a prefered embodiment of the invention, a fire alarm device is provided in which a bell or gong is sounded repetitiously at varying rates to produce an unusual and insistent rising and falling sound characteristic. This is accomplished by driving the bell or gong by a repetitive bell-ringing mechanism under the control and influence of a flywheel which is given intermittent drive pulses from a prewound spring motor. A temperature responsive trigger mechanism holds the spring motor cocked and ready. If the temperature around the device becomes dangerously high, the trigger mechanism releases an escapement to permit the spring motor to deliver a single drive impulse to the flywheel. The flywheel, thus accelerated into motion, delivers its energy to a bell-ringing mechanism at first at a rapid rate and then more slowly as the flywheel decelerates. When the angular velocity of the flywheel declines below a predetermined rate, a centrifugally responsive actuator associated with the flywheel releases the escapement to deliver another drive impulse from the spring motor to the flywheel and the cycle repeats itself. The bell-ringing mechanism under the control of the flywheel thus produces an attention-demanding sound signal first at a rapid rate and then declining, then rapid and declining again.

Although the scope of the invention in its broader aspects is measured by the claims appended hereto, further details of the invention as well as additional objects and advantages are set forth with greater clarity within the following more detailed description taken together with the accompanying drawings wherein:

FIGURE 1 is a plan view of a fire alarm device constructed in accordance with this invention and illustrated from one side revealing certain features of the interior of 3,177,842 Patented Apr. 13, 1965 the device in phantom lines, the device being shown in cocked condition;

FIGURE 2 is a detail view of a portion of FIGURE 1 showing the device after being tripped in response to a rising temperature condition;

FIGURE 3 is a cross-sectional view of the thermally responsive actuator shown in FIGURE 2;

FIGURE 4 is a plan view of the interior of the alarm device showing certain parts in section and portions of others broken away;

FIGURE 5 is a cross-sectional view taken on line 5--5 of FIGURE 4;

FIGURE 6 is a detail view of a portion of the assembly shown in FIGURE 4 illustrating certain additional details of the flywheel;

FIGURE 7 is a view similar to that of FIGURE 4 but with the flywheel shown in cross section to reveal its associated centrifugally responsive mechanism in its low-speed condition; 7

FIGURE 8 is a detail view of a portion of the assembly shown in FIGURE 7 illustrating the engagement between the centrifugally responsive flywheel mechanism and the escapement;

FIGURE 9 is a cross-sectional view taken on lines 9-9 of FIGURE 4; and

FIGURE 10 is a plan view of the underneath side of the flywheel illustrating the associated centrifugally responsive mechanism in its high-speed condition.

1 As shown in FIGURE 1, the illustrated fire alarm device includes a base plate 11 upon which are mounted an actuating assembly 12 and, represented in phantom lines on the other side of the base plate, a drive assembly 13 and a bell-ringing assembly 14. Enclosing the drive and bell-ringing assemblies is a gong or bell 15 which also functions as an enclosure. Brief reference to FIG- URES 5 and 9 will show the bell 15 to be generally bowl-shaped being supported on posts 16 fastened to the base plate. The bell cover includes freely resonant side walls which produce a ringing tone when struck. Referring back to FIGURE 1, the bell-ringing assembly may be seen to comprise a rebound-type gong pin 17 mounted for reciprocating movements to strike one of the side walls of the bell.

As seen in FIGURE 1 the actuating assembly includes a slide member 21 having a pair of aligned slots 22 and 23 extending around guide post 24 threaded into the base member 11. A bias spring 25 aflixed at one end to the slide and at the other end to post 26 on the base plate urges the slide toward the right as seen at FIGURE 1. Movements of the slide in this direction are resisted, however, by a thermally responsive device 27.

The thermally responsive device 27 is shown in cross section in FIGURE 3 as comprising piston rods 31 and 32 connected at their innermost ends to opposite sides of a piston 33 disposed within a cylinder 34. The piston 33 has an outer diameter somewhat less than the inner diameter of the cylinder 34 so as to define a restricted, annular passage 35. Cyinder heads 36 and 37, which may be fabricated of a sealing .and friction reducing material such as Teflon, may be utilized to close the ends of the cylinder 34. Lock rings 33 and 39 inserted in the ends of the cylinder prevent the movement of the cylinder heads 36 and 37 out of their installed positions. Cooperating flange portions formed respectively on the cylinder heads 36 .and 37 and on the interior of the cylinder serve to prevent further inward movement of the cylinder heads within the cylinder and to fix the extent of their separation.

An annular hardened mass 40 of fusible material composed preferably of a low melting point metallic alloy is disposed on one side of the piston 33 within the cylinder 34. The piston in cooperation with the cylinder may be considered to define a pair of cylinder cavities connected by the aforesaid restricted passage 35. In this context it is to be understood that one cylinder cavity is that portion of the interior of the cylinder between the piston 33 and the cylinder head 36, and the second cylinder cavity is that interior portion between the piston 33 and cylinder head 37. It is within the latter cylinder cavity that the fusible mass of material 40 is positioned.

As will be apparent, when the piston is disposed at either end of its travel range one of the cylinder cavities is of negligible size. However, if the ambient temperature rises to a point where the fusible mass of material 40 melts, the piston may move within this cylinder from one extreme of travel to the other and force the fusible mass of material through the restricted passageway 35 into the opposite cylinder cavity. Under such circumstances as the piston moves within the cylinder, one cavity will progressively enlarge while the other will progressively diminish in size. As long as the mass of material 4G is unmelted, however, the cylinder and piston rod assembly will resist displacement from one extreme of travel to the other.

In the low temperature condition illustrated in FIG- URE l, the cup-shaped extremity 43 of the spring biased slide 21 is urged against the resisting projecting end of piston rod 31. The opposite end of the cylinder 34 nests against a bifiurcated bracket 44 fastened by a machine screw 45 to the base plate 11. Piston rod 32 extends between the parallel bifurcated extensions of the bracket 44. against which the cylinder 34 rests. As long as the fusible material within the cylinder 34 is unmounted the thermally responsive device 27 resists the tendency of the actuating slide 21 to move to the right. When the ambient temperature rises sufiiciently to melt the fusible mass 40 within the cylinder, the resistance is overcome and the slide, under the urging of the bias spring 25, moves to the right and occupies the position shown in FIGURE 2. This is the movement of the actuating assembly which triggersthe operation of the fire alarm device with consequences to be described.

In moving to the right the, slide 21 releases a springbiased trigger 46. This trigger is fastened to shaft 47 journalled in the base plate and extending through the base plate to the other side. On the other end of the shaft 47 an escapement 48 is mounted for controlling the release of energy in discrete impulses from the drive assembly. Upon movement of the slide 21 to the right the trigger 46 is released from its engagement between the spring detent 49 on the one side and the sear arm 50 integral with slide 21 which. extends around and engages the opposite side of the trigger. Ordinarily, the trigger 46 is precisely positioned by the detent and sear in the position shown in FIGURE 1. When released by movement of the slide, however, the trigger moves counterclockwise in the direction of the arrow shown in FIGURE 2 to the position which it occupies in the latter figure.

Turning now to FIGURE 4, the cooperation between the escapment 48 and the drive assembly 13 may be more clearly seen. In this figure and in FIGURE the mechanism is shown in its latched position before being triggered to sound an alarm. The drive assembly comprises a spring-motor unit journalled for controllable move ments about shaft 51 fixed to the base plate. The springmotor unit includes an outer rotatable spring housing 52 within which is positioned a spiral spring 53. Superfluous detail has been omitted from the figure, but it is to be under stood that the spiral spring 53 is attached at its outermost end to the spring housing 52 and at its innermost end to a tensioning assembly such as a one-way clutch or ratchet. The spring 53 is placed under tension by winding it, preferably from the other side of the base plate. Brief reference to FIGURE 1 will disclose a hexagonal winding socket 54 into which a winding key with cooperating surfaces may be inserted for the purpose of placing the spring 53 under tension.

Referring back to FIGURE 4, the spring-motor housing 52 is urged in a counterclockwise direction when the spring 53 is wound. Movements of the spring housing are however prevented by the latching engagement between one of the notches 55 in the periphery of the spring housing and the hook 56 on one arm of the escapement 4S. Mounted on top of the rotatable spring-motor housing 52 is a drive gear 60 which is fixed to the springmotor housing for movement therewith. Drive gear 60 engages a spur gear 61 rotatably mounted on stationary post 62 aflixed to the base plate. When the spur gear 61 is set in motion by drive gear 60, it transmits that motion through a spring 63 to transmission gear 64. The spring 62 as can be seen in FIGURE 9 is fitted closely around a collar 65 on the spur gear 61 and the upper end of the spring is attached directly to the transmission gear 64. This arrangement provides a well-known type of slip clutch which provides a unidirectional torguetransmitting drive connection between the spur gear 61 and the transmission gear 64. Transmission gear 64 meshes in turn with an additional spur gear 66 fitted to a flywheel 67. The flywheel and its associated spur gear are journalled on shaft 51 for rotation thereon independently of movements of the spring motor.

The permissible motion of the transmission gear 63 is clockwise as shown in FIGURE 4. Each revolution of the transmission gear 64 carries depending pin 70 into engagement with an arm 71 of bell crank 72 which is journalled on shaft 73 affixed to the base plate. An opposite arm 74 of the bell crank carries a downwardly extending bifurcated projection which engages the rebound type gong pin 17 between a pair of stop members 76 and 77 thereon. The gong pin 17 is mounted for reciprocating movements within an aperture 80 in the stationary post 62 and another aperture in bracket 81 aflixed to the base plate. Helical spring 82 extending around a portion of the bell-ringing pin 17 bears at one end against the stop member 77 and at the other end against the stationary post 62 urging the pin 17 to the position shown in FIGURES 4 and 5. In this position the left-hand end of the gong pin is out of contact with the bell 15 but spaced only a short distance therefrom.

As the depending pin 70 is carried in its clockwise course about its axis of rotation it engages the arm 71 of the bell crank and moves it to the right as shown in FIGURE 7. As a result the opposite am 74 of the bell crank pulls the gong pin 17 back against the bias of spring 82. Further clockwise rotation of pin 70 releases bell crank 72 and thereby permits spring 82 to relax and throw the gong pin outward thereby to strike the bell 15 and ring it. This action compresses rebound spring 83 located between the bracket 81 and stop member 76, whereupon the rebound spring immediately returns the gong pin to the position shown in FIGURES 4 and 5.

This repetitive cocking and tripping bell-ringing action, it can be seen, is proportional in its rate to the angular velocity of the transmission gear 64 since the bell is struck once for each complete revolution of the transmis sion gear. The rate of revolution of the transmission gear 64 is in turn proportional to that of flywheel 66 to which the transmission gear is interconnected through spur gear 66. The transmission gear 64 and the flywheel 67 receive the. rotational energy impulses from the spring motor as follows.

The impulses provided by the spring motor are controlled by the escapement 48 in its cooperative relationship to the notched sections 55 spaced at equal intervals about the periphery of the rotatable spring motor housing 52. When the trigger 46 is released a helical spring wound about the journal for shaft 47 bears against arm 91 of the escapement and lifts the hooked-shaped end of arm 56 out of engagement with the slot 55 in which it is positioned. Immediately the spring 53 within the drive motor assembly begins to relax and set in motion the train of gears 60, 61, 64 and 66. The amount by which the spring is permitted to relax is limited however by the engagement of the end of arm 91 with one of the slots 55 in the periphery of the spring motor. This is illustrated in FIGURES 6 and 7.

In FIGURE 6 it can be seen that arm 56 has just been released from engagement with one of the slots 55 whereas arm 91 of the escapement 48 is in sliding engagement with the counterclockwise rotating periphery of the drive motor housing 52. As the spring in the motor continues to relax, arm 91 is urged into one of the notches 55 under the influence of spring 90 and further rotational motion of the drive motor is arrested. The single drive impulse thus imparted to the flywheel 67 and transmission gear 64 quickly accelerates these two members. From the comparative sizes of meshing gears 60 and 61 and of gears 64 and 66, it wiil be appreciated that a substantial motion amplification takes place and that flywheel 67 is brought to a fairly high angular Velocity as a result of the short drive impulses it receives.

The bell-ringing assembly 14 is therefore set into repetitive reciprocating motion at an accelerating rate until the transmission gear 64 and the flywheel 67 reach their maximum angular velocities as a result of the impulse given them. Thereafter the angular momentum of the flywheel forces the flywheel and transmission gear to continue in motion because of their respective free-wheeling connections. It is to be remembered that the transmission gear 64 can continue rotating in the same direction, despite the fact that spur gear 61 has stopped, because of the one-way clutch arrangement provided by helical spring 63. The flywheel 67, being independently journalled on shaft 51, rotates independently of the drive motor. Consequently, the flywheel 67 keeps the transmission gear 64 in motion but at a gradually decreasing rate. The frequency with which the bell is struck declines as the flywheel gives up its energy to the bell ringing operation.

Associated with the flywheel 67 is a centrifugally responsive assembly which triggers another drive impulse from the spring motor when the angular velocity of the flywheel drops below a predetermined level. As seen in FIGURE 6 the flywheel 67 is hollow and contains within its interior a pair of masses 101 and 102 mounted for limited pivotal movement on pivot pins 103 and 104 respectively. Associated with each of these masses is a biasing spring 105 urging the masses inwardly toward the center or" the flyw eel. These biasing springs are positioned within slots in each of the pivoted masses and bear against sliding spring-seat pins 106 which are in contact with an inner surface of the flywheel 67.

Each of the masses 101 and 102, although urged inwardly by its associated bias spring 105, is free to move radially outward from the center of the flywheel 67 under the influence of centrifugal forces resulting from rapid rotation of the flywheel. To insure that both masses pivot outward or inward simultaneously, thereby to prevent an imbalance of the flywheel, a double-ended lever 110 is rotatably journalled on hearing 111 around an internal hub 112 of the flywheel. The double-ended lever carries at each end a crank pin 113 engaging the walls of slots formed in inwardly extending arms 114 of the respective pivoted masses. Consequently an inward or outward movement of either one of the masses is accompanied by a similar movement of the other mass.

When the flywheel is at rest or when it is rotating with a relatively low velocity, the masses 101 and 102 occupy the relative positions shown in FIGURES 6, 7 and 8. At such times a release pin 120 on an extension 121 of mass 101 is located close to the periphery of the flywheel 67. When the flywheel exceeds a predetermined angular velocity, however, masses 101 and 102 pivot outwardly and in doing so they move extension 121 and release pin 120 inward toward the center of the flywheel. The relative disposition of parts in the flywheel at such times is shown in FIGURE 10 which is a view of the flywheel assembly from beneath. Upon initial triggering by the condition responsive assembly device when the spring motor delivers a specific initial impulse to the flywheel and thus to the bell-ringing assembly, the flywheel quickly accelerates to a high speed condition beyond the angular velocity at which the masses 101 and 102 move outwardly.

Thereafter, as the flywheel gradually delivers its energy through the transmission gear to the bell-ringing assembly, it slows to a point at which the masses 101 and 102 pivot inwardly under the influence of their bias springs. The release pin then moves outwardly from the center of the flywheel to its low speed position. The release pin is then in a position, as can be seen in FIGURES 7 and 8, to engage an additional trip arm 122 fixed on shaft 47 to move with the escapement 48. Release pin 120 moves counterclockwise as seen in these two figures to strike the cam surface 123 at the end of trip arm 122, and the pin 120 rides up and over this cam surface to move the trip arm in a counterclockwise direction. As trip arm 122 is moved counterclockwise it lifts the projecting end of arm 91 of the escapement 43 out of engagement with slot 55, thereby permitting the spring motor to deliver another drive impulse to the train of gears and to set in operation another cycle of the bell-ringing operation.

Of course, as soon as the release pin 120 passes beyond its engagement with the end of release lever 122, both the release lever 122 and the escapement 48 return under the urging of spring to the positions shown in FIGURE 6, whereupon an engagement once again occurs between arm 91 and one of the notches 55 in the outer periphery of the spring motor. This results in limiting the drive impulse delivered by the spring motor and delays the delivery of additional impulses until the flywheel slows to an extent suflicient to retrigger the mechanism.

It can be seen, therefore, that the bell receives repetitious impacts from the rebound-type bell ringing pin 17 increasing in rate as the flywheel accelerates and then decreasing followed by subsequent increases and decreases in rate. The character of the sound produced by the sound mechanism thus has an insistent attention-demanding quality which cannot easily be ignored.

The entire device as shown and described herein constitutes a compact and self-contained alarm mechanism for responding to an emergency condition such as a fire. Although the invention is especially valuable for the signalling of fire alarms, it will be recognized by those skilled in the arts to which this invention pertains that the invention is also useful for signalling other emergencies. For example, in place of the thermally responsive actuator device 27 other condition responsive elements could be inserted to trigger the mechanism in response to conditions such as, for example, changes in fluid pressure in a hydraulic system or currents in an electrical system. The alarm device can even be used as a burglar alarm with very little variation in the triggering mechanism to be tripped to sound an alarm when an unauthorized entry is made into an enclosure.

Since certain variations and modifications may be made not only within the structure of the device itself but also in its applications, it is to be understood that the embodiment described herein is offered primarily as illustrative of the invention and that the appended claims are intended to cover all such variations and modifications as fall within the true spirit and scope of the invention in its broader aspects. 7

What is claimed is:

1. A condition responsive warning device comprising:

a warning bell;

a ringer for said bell,

means including a flywheel for operating said bell ringer repetitively at a rate proportional to the rate of rotation of said flywheel,

means for supplying drive impulses to said flywheel including a stored energy motor; and

wheel upon the occurrence of a predetermined con-- dition; and

centrifugally operated means responsive to the motion of said flywheel for operating said releasing means when said flywheel slows below a predetermined rate of rotation, whereby upon the occurrence of said condition said ringer operates said bell at alter-- nately rising and falling rates.

2. A condition responsive warning device comprising:

a warning bell;

a bell ringer for sounding said bell,

means including a flywheel for operating said bell? ringer repetitively, the rate of operation of said belll ringer being proportional to the rate of rotation: of said flywheel,

means for supplying drive impulses to said flywheel including a spring motor; and

escapement means operable when tripped to release said spring motor momentarily to provide an incremental drive impulse to said flywheel;

condition responsive means for tripping said escapement means to provide an initial impulse to said flywheel impulse to said flywheel upon the occurrence of a predetermined condition; and

centrifugally operated means responsive to the motion of said flywheel for tripping said escapement means when said flywheel slows below a predetermined angular velocity, whereby upon the occurrence of said condition said bell ringer sounds said bell at alternately rising and falling rates.

3. A condition responsive device comprising, in combination:

a stored energy motor;

escapement means normally arresting operation of said motor and operable when tripped to release said motor momentarily to produce an incremental drive impulse;

a rotatably mounted flywheel;

motion transmitting means for accelerating said flywheel in response to drive impulses of said motor, said motion transmitting means including unidirectional torque transmitting means to allow said flywheel to continue its rotation after the termination of a drive impulse;

condition responsive means for tripping said escapement means to provide an initial impulse to said flywheel upon the occurrence of a predetermined condition;

a centrifugally operated trip member responsive to movements of said flywheel to trip said escapement means when said flywheel decelerates below .a predetermined angular velocity;

a warning bell; and

a bell ringer governed by said flywheelto sound said warning bell repetitively at rates proportional to the rate of rotation of said flywheel, whereby said bell ringer sounds said warning bell at alternately accelerating and decelerating rates to produce an insistent attention-demanding alarm.

4. A condition responsive alarm device comprising,

in combination:

a spring motor;

escapement means normally arresting operation of said spring motor and operable when tripped to release said spring motor momentarily to produce an incremental drive impulse;

a rotatably mounted flywheel;

motion transmitting means including a unidirectional torque-transmitting connection between said spring motor and said flywheel for accelerating said flywheel in response to an incremental drive impulse from said spring motor, whereby said flywheel continues its rotation after the termination of a drive impulse;

condition responsive means for tripping said escapement means to provide an initial drive impulse to said flywheel upon the occurrence of a predetermined condition;

a centrifugally operated trip member responsive to movements of said flywheel to trip said escapement means when said flywheel decelerates below a predetermined angular velocity;

a warning bell; and

a bell ringer governed by said flywheel and driven thereby to strike said warning bell repetitively at rates proportional to the rates of rotation of said flywheel, whereby said bell ringer strikes said warning bell at alternately accelerating and decelerating rates to produce an insistent attention-demanding alarm.

5. A condition responsive alarm device comprising,

in combination:

a spring motor including a drive spring and a rotatable drive gear driven by said drive spring;

escapement means normally arresting movements of said drive gear and operable when tripped to release said drive gear momentarily to produce an incremental drive impulse;

a rotatably mounted flywheel;

motion transmitting means including a unidirectional torque-transmitting connection between said drive gear and said flywheel for accelerating said flywheel in response to a drive impulse of said drive gear and to permit said flywheel to continue its rotation after the termination of such drive impulse;

condition responsive means for tripping said escapement means to provide an initial impulse to said flywheel upon the occurrence of a predetermined condition;

a centrifugally operated trip member responsive to motion of said flywheel for tripping said escapement means when said flywheel decelerates below a predetermined angular velocity;

a warning bell; and

a bell ringer governed by said flywheel and driven vthereby to strike said warning bell repetitively at rates proportional to the rate of rotation of said flywheel whereby upon the occurrence of said condition said bell ringer strikes said warning bell at alternately accelerating and decelerating rates to produce an insistent attention-demanding alarm.

6. A fire alarm device comprising, in combination:

a spring motor including a drive spring and a rotatable drive member driven by said drive spring;

escapement means normally arresting said drive memher and operable when tripped to release said drive member momentarily for an incremental driving movement;

a rotatably mounted flywheel;

motion transmitting means including a unidirectional torque-transmitting clutch connecting said flywheel to receive an accelerating drive impulse from each incremental driving movement of said drive member, whereby said flywheel continues its rotation after the termination of such drive impulse;

a warning bell;

a bell ringer governed by said flywheel for sounding said warning bell repetitively at rates proportional to the angular velocity of said flywheel;

condition responsive means operable in response to an increase in temperature above a predetermined level to trip said escapement means; and

a centrifugally responsive trip member responsive to the motion of said flywheel to trip said escapement means to release said drive member for an. incremental driving movement when said flywheel decelerates below a predetermined angular velocity, whereby said spring motor delivers recurrent drive impulses to said flywheel thereby sounding said warning bell at alternately accelerating and decelerating rates.

7. A fire alarm device comprising, in combination:

a spring motor including a drive spring and a rotatable drive member driven by said drive spring for delivering energy from said motor;

escapement means normally arresting said drive member and operable when tripped to release said drive member for an incremental driving movement;

a rotatably mounted flywheel;

motion transmitting means including a unidirectional clutch connecting said flywheel to receive an accelerating drive impulse from each incremental driving movement of said drive member, whereby said flywheel continues its rotation after the termination of such drive impulse;

a warning bell;

a bell ringer governed by said flywheel for striking said warning bell repetitively at rates proportional to the angular velocity of said flywheel;

condition responsive means operable in response to an increase in temperature above a predetermined level to trip said escapement means; and

a centrifugally responsive trip member carried by said flywheel and movable thereon between radially spaced-apart low-speed and high-speed positions in response to the rate of rotation of said flywheel, said trip member when in said low-speed position being engageable with said escapement means to release said drive member for an incremental driving movement, whereby when the temperature exceeds said predetermined level said spring motor delivers re- 1% current drive impulses to said flywheel thereby ringing said Warning bell at alternately accelerating and decelerating rates.

8. A temperature-sensitive alarm device comprising:

a spring motor including a stored energy drive spring;

escapement means operable when tripped to release an incremental drive impulse from said motor;

a rotatably mounted transmission gear;

motion transmitting means including a unidirectional torque-transmitting connection coupling said transmission gear to said spring motor to receive drive impulses;

a warning bell;

a reciprocable bell ringer for sounding said bell;

an operating member carried by said transmission gear to operate said bell ringer on each rotation of said transmission gear;

a flywheel geared to said transmission gear for pro portionate angular movements therewith;

a thermally responsive actuator operable to trip said escapement means when the temperature exceeds a predetermined level thereby to give an initial drive impulse to said transmission gear and said flywheel; and

a centrifugally responsive actuator responsive to the motion of said flywheel for tripping said escapement means when said flywheel decelerates below a predetermined angular velocity, thereby to give subsequent drive impulses to said transmission gear and flywheel, whereby said bell ringer sounds said warning bell repetitively at alternately accelerating-and decelerating rates to produce an insistent attentiondemanding alarm.

No references cited. 

1. A CONDITION RESPONSIVE WARNING DEVICE COMPRISING: A WARNING BELL; A RINGER FOR SAID BELL, MEANS INCLUDING A FLYWHEEL FOR OPERATING SAID BELL RINGER REPETITIVELY AT A RATE PROPORTIONAL TO THE RATE OF ROTATION OF SAID FLYWHEEL, MEANS FOR SUPPLYING DRIVE IMPULSES TO SAID FLYWHEEL INCLUDING A STORED ENERGY MOTOR; AND MEANS FOR RELEASING AN INCREMENT OF ENERGY STORED IN SAID MOTOR TO PROVIDE A DRIVE IMPULSE TO SAID FLYWHEEL; CONDITION RESPONSIVE MEANS FOR OPERATING SAID RELEASING MEANS TO PROVIDE AN INITIAL IMPULSE TO SAID FLYWHEEL UPON THE OCCURRENCE OF A PREDETERMINED CONDITION; AND CENTRIFUGALLY OPERATED MEANS RESPONSIVE TO THE MOTION OF SAID FLYWHEEL FOR OPERATING SAID RELEASING MEANS WHEN SAID FLYWHEEL SLOWS BELOW A PREDETERMINED RATE OF ROTATION, WHEREBY UPON THE OCCURRENCE OF SAID CONDITION SAID RINGER OPERATES SAID BELL AT ALTERNATELY RISING AND FALLING RATES. 